DEFER_CAPABILITY_MISSING

What failed

An active Crux scope exists, but it cannot support the requested defer() form.

Common cases:

• Inline defer(callback) on Convex or Lambda named-only hosts
• Missing waitUntil / after port
• Named work on a host with durableFinalization: false
• Async scope without a lifetime capability facet

Why

Crux refuses to advertise reliability a host cannot provide. Inline closures are not durable; named work needs durable finalization before response commit.

What still works

• The other overload when the host supports it (named on Convex/Lambda with Runtime)
• Hosts with full lifetime ports for inline work
• flow.defer() for replay-safe durable flow children

Fix

1. Inline unsupported: switch to await defer(target, input) with Runtime, or move the work to a host that supports inline drain.
2. Missing port: pass an explicit waitUntil / after into @use-crux/core/defer/serverless or use @use-crux/next.
3. Named without durability: enable durableFinalization: true on a Runtime- capable host integration and configure config({ runtime }).

See hosts and troubleshooting.